1951a39d68df598db08dfced8b4707755864a0492Ying Wang// Support for atomic operations -*- C++ -*- 2951a39d68df598db08dfced8b4707755864a0492Ying Wang 3951a39d68df598db08dfced8b4707755864a0492Ying Wang// Copyright (C) 2004, 2005, 2006, 2008, 2009 Free Software Foundation, Inc. 4951a39d68df598db08dfced8b4707755864a0492Ying Wang// 5951a39d68df598db08dfced8b4707755864a0492Ying Wang// This file is part of the GNU ISO C++ Library. This library is free 6951a39d68df598db08dfced8b4707755864a0492Ying Wang// software; you can redistribute it and/or modify it under the 7951a39d68df598db08dfced8b4707755864a0492Ying Wang// terms of the GNU General Public License as published by the 8951a39d68df598db08dfced8b4707755864a0492Ying Wang// Free Software Foundation; either version 3, or (at your option) 9951a39d68df598db08dfced8b4707755864a0492Ying Wang// any later version. 10951a39d68df598db08dfced8b4707755864a0492Ying Wang 11951a39d68df598db08dfced8b4707755864a0492Ying Wang// This library is distributed in the hope that it will be useful, 12951a39d68df598db08dfced8b4707755864a0492Ying Wang// but WITHOUT ANY WARRANTY; without even the implied warranty of 13951a39d68df598db08dfced8b4707755864a0492Ying Wang// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14951a39d68df598db08dfced8b4707755864a0492Ying Wang// GNU General Public License for more details. 15951a39d68df598db08dfced8b4707755864a0492Ying Wang 16951a39d68df598db08dfced8b4707755864a0492Ying Wang// Under Section 7 of GPL version 3, you are granted additional 17951a39d68df598db08dfced8b4707755864a0492Ying Wang// permissions described in the GCC Runtime Library Exception, version 18951a39d68df598db08dfced8b4707755864a0492Ying Wang// 3.1, as published by the Free Software Foundation. 19951a39d68df598db08dfced8b4707755864a0492Ying Wang 20951a39d68df598db08dfced8b4707755864a0492Ying Wang// You should have received a copy of the GNU General Public License and 21951a39d68df598db08dfced8b4707755864a0492Ying Wang// a copy of the GCC Runtime Library Exception along with this program; 22951a39d68df598db08dfced8b4707755864a0492Ying Wang// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23951a39d68df598db08dfced8b4707755864a0492Ying Wang// <http://www.gnu.org/licenses/>. 24951a39d68df598db08dfced8b4707755864a0492Ying Wang 25951a39d68df598db08dfced8b4707755864a0492Ying Wang/** @file atomicity.h 26951a39d68df598db08dfced8b4707755864a0492Ying Wang * This is an internal header file, included by other library headers. 27951a39d68df598db08dfced8b4707755864a0492Ying Wang * You should not attempt to use it directly. 28951a39d68df598db08dfced8b4707755864a0492Ying Wang */ 29951a39d68df598db08dfced8b4707755864a0492Ying Wang 30951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifndef _GLIBCXX_ATOMICITY_H 31951a39d68df598db08dfced8b4707755864a0492Ying Wang#define _GLIBCXX_ATOMICITY_H 1 32951a39d68df598db08dfced8b4707755864a0492Ying Wang 33951a39d68df598db08dfced8b4707755864a0492Ying Wang#include <bits/c++config.h> 34951a39d68df598db08dfced8b4707755864a0492Ying Wang#include <bits/gthr.h> 35951a39d68df598db08dfced8b4707755864a0492Ying Wang#include <bits/atomic_word.h> 36951a39d68df598db08dfced8b4707755864a0492Ying Wang 37951a39d68df598db08dfced8b4707755864a0492Ying Wang_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 38951a39d68df598db08dfced8b4707755864a0492Ying Wang 39951a39d68df598db08dfced8b4707755864a0492Ying Wang // Functions for portable atomic access. 40951a39d68df598db08dfced8b4707755864a0492Ying Wang // To abstract locking primitives across all thread policies, use: 41951a39d68df598db08dfced8b4707755864a0492Ying Wang // __exchange_and_add_dispatch 42951a39d68df598db08dfced8b4707755864a0492Ying Wang // __atomic_add_dispatch 43951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifdef _GLIBCXX_ATOMIC_BUILTINS_4 44951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline _Atomic_word 45951a39d68df598db08dfced8b4707755864a0492Ying Wang __exchange_and_add(volatile _Atomic_word* __mem, int __val) 46951a39d68df598db08dfced8b4707755864a0492Ying Wang { return __sync_fetch_and_add(__mem, __val); } 47951a39d68df598db08dfced8b4707755864a0492Ying Wang 48951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline void 49951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add(volatile _Atomic_word* __mem, int __val) 50951a39d68df598db08dfced8b4707755864a0492Ying Wang { __sync_fetch_and_add(__mem, __val); } 51951a39d68df598db08dfced8b4707755864a0492Ying Wang#else 52951a39d68df598db08dfced8b4707755864a0492Ying Wang _Atomic_word 53951a39d68df598db08dfced8b4707755864a0492Ying Wang __attribute__ ((__unused__)) 54951a39d68df598db08dfced8b4707755864a0492Ying Wang __exchange_and_add(volatile _Atomic_word*, int); 55951a39d68df598db08dfced8b4707755864a0492Ying Wang 56951a39d68df598db08dfced8b4707755864a0492Ying Wang void 57951a39d68df598db08dfced8b4707755864a0492Ying Wang __attribute__ ((__unused__)) 58951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add(volatile _Atomic_word*, int); 59951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 60951a39d68df598db08dfced8b4707755864a0492Ying Wang 61951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline _Atomic_word 62951a39d68df598db08dfced8b4707755864a0492Ying Wang __exchange_and_add_single(_Atomic_word* __mem, int __val) 63951a39d68df598db08dfced8b4707755864a0492Ying Wang { 64951a39d68df598db08dfced8b4707755864a0492Ying Wang _Atomic_word __result = *__mem; 65951a39d68df598db08dfced8b4707755864a0492Ying Wang *__mem += __val; 66951a39d68df598db08dfced8b4707755864a0492Ying Wang return __result; 67951a39d68df598db08dfced8b4707755864a0492Ying Wang } 68951a39d68df598db08dfced8b4707755864a0492Ying Wang 69951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline void 70951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add_single(_Atomic_word* __mem, int __val) 71951a39d68df598db08dfced8b4707755864a0492Ying Wang { *__mem += __val; } 72951a39d68df598db08dfced8b4707755864a0492Ying Wang 73951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline _Atomic_word 74951a39d68df598db08dfced8b4707755864a0492Ying Wang __attribute__ ((__unused__)) 75951a39d68df598db08dfced8b4707755864a0492Ying Wang __exchange_and_add_dispatch(_Atomic_word* __mem, int __val) 76951a39d68df598db08dfced8b4707755864a0492Ying Wang { 77951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifdef __GTHREADS 78951a39d68df598db08dfced8b4707755864a0492Ying Wang if (__gthread_active_p()) 79951a39d68df598db08dfced8b4707755864a0492Ying Wang return __exchange_and_add(__mem, __val); 80951a39d68df598db08dfced8b4707755864a0492Ying Wang else 81951a39d68df598db08dfced8b4707755864a0492Ying Wang return __exchange_and_add_single(__mem, __val); 82951a39d68df598db08dfced8b4707755864a0492Ying Wang#else 83951a39d68df598db08dfced8b4707755864a0492Ying Wang return __exchange_and_add_single(__mem, __val); 84951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 85951a39d68df598db08dfced8b4707755864a0492Ying Wang } 86951a39d68df598db08dfced8b4707755864a0492Ying Wang 87951a39d68df598db08dfced8b4707755864a0492Ying Wang static inline void 88951a39d68df598db08dfced8b4707755864a0492Ying Wang __attribute__ ((__unused__)) 89951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add_dispatch(_Atomic_word* __mem, int __val) 90951a39d68df598db08dfced8b4707755864a0492Ying Wang { 91951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifdef __GTHREADS 92951a39d68df598db08dfced8b4707755864a0492Ying Wang if (__gthread_active_p()) 93951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add(__mem, __val); 94951a39d68df598db08dfced8b4707755864a0492Ying Wang else 95951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add_single(__mem, __val); 96951a39d68df598db08dfced8b4707755864a0492Ying Wang#else 97951a39d68df598db08dfced8b4707755864a0492Ying Wang __atomic_add_single(__mem, __val); 98951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 99951a39d68df598db08dfced8b4707755864a0492Ying Wang } 100951a39d68df598db08dfced8b4707755864a0492Ying Wang 101951a39d68df598db08dfced8b4707755864a0492Ying Wang_GLIBCXX_END_NAMESPACE 102951a39d68df598db08dfced8b4707755864a0492Ying Wang 103951a39d68df598db08dfced8b4707755864a0492Ying Wang// Even if the CPU doesn't need a memory barrier, we need to ensure 104951a39d68df598db08dfced8b4707755864a0492Ying Wang// that the compiler doesn't reorder memory accesses across the 105951a39d68df598db08dfced8b4707755864a0492Ying Wang// barriers. 106951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifndef _GLIBCXX_READ_MEM_BARRIER 107951a39d68df598db08dfced8b4707755864a0492Ying Wang#define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory") 108951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 109951a39d68df598db08dfced8b4707755864a0492Ying Wang#ifndef _GLIBCXX_WRITE_MEM_BARRIER 110951a39d68df598db08dfced8b4707755864a0492Ying Wang#define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory") 111951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 112951a39d68df598db08dfced8b4707755864a0492Ying Wang 113951a39d68df598db08dfced8b4707755864a0492Ying Wang#endif 114